Utilities - Spacing

Overview

>Spacing includes a wide range of shorthand responsive margin, padding, and gap utility classes to modify an element’s appearance.

Notation

Spacing utilities that apply to all breakpoints, from xs to xxl, have no breakpoint abbreviation in them. This is because those classes are applied from min-width: 0 and up, and thus are not bound by a media query. The remaining breakpoints, however, do include a breakpoint abbreviation.

The classes are named using the format {property}{sides}-{size} for xs and {property}{sides}-{breakpoint}-{size} for sm, md, lg, xl, and xxl.

Where property is one of:

m - for classes that set margin
p - for classes that set padding

Where sides is one of:

t - for classes that set margin-top or padding-top
b - for classes that set margin-bottom or padding-bottom
s - (start) for classes that set margin-left or padding-left in LTR, margin-right or padding-right in RTL
e - (end) for classes that set margin-right or padding-right in LTR, margin-left or padding-left in RTL
x - for classes that set both *-left and *-right
y - for classes that set both *-top and *-bottom
blank - for classes that set a margin or padding on all 4 sides of the element

Where size is one of:

0 - for classes that eliminate the margin or padding by setting it to 0
1 - for classes that set the margin or padding to 0.25rem
2 - for classes that set the margin or padding to 0.5rem
3 - for classes that set the margin or padding to 0.75rem
4 - for classes that set the margin or padding to 1rem
Continue in this manner until 20.20 - for classes that set the margin or padding to 5rem
auto - for classes that set the margin to auto

Examples

Here are some representative examples of these classes:

.mt-0 {
margin-top: 0 !important;
}

.ms-1 {
margin-left: ($spacer * .25) !important;
}

.px-2 {
padding-left: ($spacer * .5) !important;
padding-right: ($spacer * .5) !important;
}

.p-3 {
padding: $spacer !important;
}

Horizontal centering

Additionally, Bootstrap also includes an .mx-auto class for horizontally centering fixed-width block level content—that is, content that has display: block and a width set—by setting the horizontal margins to auto.

Centered element

<div class="mx-auto" style="width: 200px;">
Centered element
</div>

Negative margin

In CSS, margin properties can utilize negative values (padding cannot). These negative margins are disabled by default, but can be enabled in Sass by setting $enable-negative-margins: true.

The syntax is nearly the same as the default, positive margin utilities, but with the addition of n before the requested size. Here’s an example class that’s the opposite of .mt-1:

.mt-n1 {
margin-top: -0.25rem !important;
}